By Karen Freifeld

NEW YORK (Reuters) - Lawyers for Republican presidential candidate Donald Trump on Monday filed court papers opposing the release of video showing him being questioned under oath about his Trump University series of real estate seminars.

They argued that making public the videos, for which written transcripts are already available, would prejudice Trump's case. The video is "unnecessary, irrelevant and unjustified," lawyers for Trump wrote in court papers filed in federal court in San Diego.

In legal proceedings, evidence is considered prejudicial if it may interfere with a judge or jury's objective consideration of the facts. Such evidence can still be presented if it is considered highly relevant to the case.

The Republican candidate has already claimed the federal judge overseeing the case is biased against him because of the judge's Mexican heritage.

Trump may also have concerns about the impact the videos could have outside the courtroom. On Friday, CNN, CBS, the New York Times, and other media outlets asked for the complete deposition transcripts and videotapes to be made available. If released, the videos could provide fodder for campaign commercials against Trump.

In lawsuits in California and New York, Trump has been accused of bilking students who paid as much as $35,000 for an opportunity to learn the businessman's real estate investment strategies. Former Trump University students suing the billionaire claim that they learned little and that their instructors, supposedly hand-picked by Trump, had few qualifications.

During deposition, Trump has admitted that he did not select instructors. His lawyers have argued the "hand-picked" claim amounted to mere sales "puffery" rather than fraud.

In court papers arguing for the videos' release, lawyers for the students argued the images presented nuances not available in the transcripts. "Trump's tone, facial expressions, gestures and body language... speak volumes to... Trump's complete and utter unfamiliarity with the instructors and 'instruction' that student-victims received," they said.

Trump has said the claims over Trump University are baseless and that students highly rated the programs.

The case is Art Cohen v Donald J. Trump, 13-cv-2519, U.S. District Court, Southern District of California.

(Reporting By Karen Freifeld; Editing by Anthony Lin and David Gregorio)